Difference between revisions of "Glioma"

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==Classification==
==Classification==


Gliomas are classified by cell type, by WHO grade, and by location.
Gliomas are classified by cell type, by CNS WHO grade, patient age and by location.


===By type of cell===
===By type of cell===
Gliomas are named according to the specific type of cell with which they share histological features, but not necessarily from which they originate. The main types of gliomas are:
Gliomas are named according to the specific type of cell with which they share histological features, but not necessarily from which they originate. The main types of gliomas are:


* [[Astrocytoma]]s—[[astrocyte]]s ([[glioblastoma multiforme]] is a malignant astrocytoma and the most common primary brain tumor among adults).
* [[Glioblastoma]] is a malignant astrocytoma and the most common primary brain tumor among adults.
* [[Oligodendroglioma]]s—[[oligodendrocyte]]s
* [[Astrocytoma]]s—[[astrocyte]]s.
* [[Ependymoma]]s—ependymal cells
* [[Oligodendroglioma]]s—[[oligodendrocyte]]s.
* Mixed gliomas, such as [[oligoastrocytoma]]s, contain cells with different morphologies
* [[Ependymoma]]s—ependymal cells.
**Molecular analysis allows the tumor in most cases assigned to astrocytoma or oligodendroglioma.
* Glioneuronal and neuronal tumors.


Note:
Note:
Some authors consider [[choroid plexus]] as a specific type of glia, but [[choroid plexus tumors]] are usually not covered under the umberella term '''glioma'''.
Some authors consider [[choroid plexus]] as a specific type of glia, but [[choroid plexus tumors]] are usually not covered under the umberella term '''glioma'''.


===By WHO grade===
===By CNS WHO grade===
Gliomas are further categorized according to their grade, which is determined by [[pathology|pathologic]] evaluation of the tumor.
Gliomas are further categorized according to their grade, which is determined by [[pathology|pathologic]] evaluation of the tumor. Of numerous grading systems in use, the most common is the [[World Health Organization]] (WHO) grading system under which tumors are graded from 1 (least advanced disease—best prognosis) to 4 (most advanced disease—worst prognosis). Historically roman numerals were used for grading, but have been replaced by arabic numerals for grading within tumor types. Specific molecular features may influence tumor grading which is now a combination of histology and molecular neuroathology. Grading is based on expected biological behaviour, although proper treatment may heavily change prognosis.


*Low-grade gliomas [WHO grade II] are well-differentiated (not anaplastic);  these tend to exhibit  [[cancer|benign]] tendencies and portend a better prognosis for the patient. However, they have a uniform rate of recurrence and increase in grade over time so should be classified as malignant.  
*Low-grade gliomas [CNS WHO grade 1-2] are well-differentiated (not anaplastic);  these tend to exhibit  [[cancer|benign]] tendencies and portend a better prognosis for the patient. However, they have a uniform rate of recurrence and some diffuse gliomas may increase in grade over time and therefore calling these tumours benign is avoided.  
*High-grade [WHO grade III–IV] gliomas are undifferentiated or anaplastic;  these are [[cancer|malignant]] and carry a worse prognosis.
*High-grade [CNS WHO grade 3-4] gliomas are undifferentiated or anaplastic;  these are [[cancer|malignant]] and carry a worse prognosis.


Of numerous grading systems in use, the most common is the [[World Health Organization]] (WHO) grading system for astrocytoma, under which tumors are graded from I (least advanced disease—best prognosis) to IV (most advanced disease—worst prognosis).
===By patient age group===
The fifth CNS WHO edition recognizes following categories:
* Adult-type diffuse gliomas.
* Pediatric-type diffuse low-grade gliomas.
* Pediatric-type diffuse high-grade gliomas.
* Circumscribed astrocytic gliomas.


===By location===
===By location===
Gliomas can be classified according to whether they are above or below a membrane in the brain called the tentorium. The tentorium separates the cerebru] (above) from the cerebellum (below).
* A supratentorial tumour is above the tentorium, in the cerebrum, and mostly found in adults (70%).
* An infratentorial tumour is below the tentorium, in the cerebellum, and mostly found in children (70%).
* The pontine is located in the pons of the brainstem. The brainstem has three parts (pons, midbrain, and medulla); the pons controls critical functions such as breathing, making surgery on these extremely dangerous.


*The supratentorial is above the tentorium, in the cerebrum, and mostly found in adults (70%).
* Anatomic separation is essential in ependymal tumors. They are classfied into three groups:
*The infratentorial is below the tentorium, in the cerebellum, and mostly found in children (70%).
** Supratentorial ependymoma.
*The pontine is located in the pons of the brainstem. The brainstem has three parts (pons, midbrain, and medulla); the pons controls critical functions such as breathing, making surgery on these extremely dangerous.
** Posterior fossa ependymoma.
** Spinal ependymoma.
 
* Some gliomas have a specific anatomic designation in their name, reflecting their predominant tumor location.
** [[Diffuse hemispheric glioma, H3 G34-mutant]].
** [[Diffuse midline glioma, H3 K27-altered]].
** Infant-type hemispheric glioma.
 
 
===By Molecular profile===
Some tumors can only diagnosed after a specific alteration has been confirmed.
 
Examples are:
* Astrocytoma, IDH-mutant.
* Oligodendroglioma, IDH-mutant and 1p/19q codeleted.
* [[Diffuse hemispheric glioma, H3 G34-mutant]].
* [[Diffuse midline glioma, H3 K27-altered]].
* [[Diffuse astrocytoma, MYB- or MYBL-altered]].
* CNS tumour with BCOR internal tandem duplication.


==Table of common gliomas==
==Table of common gliomas==
Histomorphologic comparison of common gliomas:
Histomorphologic comparison of common gliomas:
{| class="wikitable"
{| class="wikitable"
|'''Entity''' || '''Rosenthal <br>fibres / EGBs''' ||'''Nuclear atypia''' ||'''Mitoses''' || '''Necrosis or MVP''' || '''Infiltrative''' || '''Image'''
|'''Entity''' || '''Rosenthal <br>fibres / EGBs''' ||'''Nuclear atypia''' ||'''Mitoses''' || '''Necrosis''' ||'''MVP''' || '''Infiltrative''' || '''Image'''
|-
|-
|[[Pilocytic astrocytoma]] || yes || usu. no || usu. no || usu. no || no || [[Image:Rosenthal_HE_40x.jpg|thumb|150px]]
|[[Pilocytic astrocytoma]] || yes || usu. no || usu. no || usu. no ||  yes || no || [[Image:Rosenthal_HE_40x.jpg|thumb|150px]]
|-
|-
|[[Diffuse astrocytoma]] || no || yes || no || no || yes || [[File:Astrocytoma_whoII_HE.jpg|thumb|150px]]
|[[Astrocytoma CNS WHO grade 2]] || no || yes || no || no  || no || yes || [[File:Astrocytoma_whoII_HE.jpg|thumb|150px]]
|-
|-
|[[Anaplastic astrocytoma]] || no || yes || yes || no || yes || [[Image:Anaplastic_astrocytoma_-_high_mag.jpg|thumb|150px]]
|[[Astrocytoma CNS WHO grade 3]] || no || yes || yes || no || no || yes || [[Image:Anaplastic_astrocytoma_-_high_mag.jpg|thumb|150px]]
|-
|-
|[[Glioblastoma]] || no || yes || yes || yes || yes || [[Image:Glioblastoma_-_high_mag.jpg|thumb|150px]]
|[[Glioblastoma]] || no || yes || yes || yes || yes || yes || [[Image:Glioblastoma_-_high_mag.jpg|thumb|150px]]
|-
|-
|[[Oligodendroglioma]] || no || usu. no || yes || no || yes || [[Image:Oligodendroglioma1_low_mag.jpg|thumb|150px]]
|[[Oligodendroglioma]] || no || usu. no || yes || no || no || yes || [[Image:Oligodendroglioma1_low_mag.jpg|thumb|150px]]
|-
|-
|[[Ependymoma]] || no || usu. no || usu. no || usu. no || discrete || [[Image:Ependymoma_H%26E.jpg|thumb|150px]]
|[[Ependymoma CNS WHO grade 2]] || no || usu. no || usu. no || usu. no || no || discrete || [[Image:Ependymoma_H%26E.jpg|thumb|150px]]
|-
|-
|[[Anaplastic ependymoma]] || no || yes || yes || usu. yes || discrete || [[Image:HE anaplastic epedymomas mitoses pleomorphism.jpg|thumb|150px]]
|[[Ependymoma CNS WHO grade 3]] || no || yes || yes || usu. yes || rare ||  discrete || [[Image:HE anaplastic epedymomas mitoses pleomorphism.jpg|thumb|150px]]
|}
|}
Notes:
Notes:
*''MVP'' = microvascular proliferation.
*''MVP'' = microvascular proliferation.
*''EGBs'' = eosinophilic granular bodies.
*''EGBs'' = eosinophilic granular bodies.
==Frequency==
The relative frequency differs significantly between adults and children.<ref>{{Cite journal  | last1 = Ostrom | first1 = QT. | last2 = Gittleman | first2 = H. | last3 = Liao | first3 = P. | last4 = Rouse | first4 = C. | last5 = Chen | first5 = Y. | last6 = Dowling | first6 = J. | last7 = Wolinsky | first7 = Y. | last8 = Kruchko | first8 = C. | last9 = Barnholtz-Sloan | first9 = J. | title = CBTRUS statistical report: primary brain and central nervous system tumors diagnosed in the United States in 2007-2011. | journal = Neuro Oncol | volume = 16 Suppl 4 | issue =  | pages = iv1-63 | month = Oct | year = 2014 | doi = 10.1093/neuonc/nou223 | PMID = 25304271 }}</ref>
*Adults:
** glioblastoma 55.2%
** astrocytoma grade II 9%
** anaplastic astrocytoma grade III 6.1%
** ependymoma 6.8%
** oligodendroglioma grade II 5.9%
** pilocytic astrocytoma 5.9%
** anaplastic oligodendroglioma grade III 3.3%
** not further specified 8.4%
*Children:
** pilocytic astrocytoma 33.8%
** malignant glioma, NOS 25.7%
** ependymoma 11.4%
** astroyctoma grade II 11.1%
** glioblastoma 6.3%
** oligodendroglioma  3.9%
** anaplastic astrocytoma grade III 3.6%
** not further specified 4.2%


==See also==
==See also==

Latest revision as of 08:33, 4 April 2022

A glioblastoma, the most common glioma. (WC/sbrandner)

Gliomas are the most compon primary tumor in the brain and spinal cord. They originate from glial cells and their precursors.

Classification

Gliomas are classified by cell type, by CNS WHO grade, patient age and by location.

By type of cell

Gliomas are named according to the specific type of cell with which they share histological features, but not necessarily from which they originate. The main types of gliomas are:

Note: Some authors consider choroid plexus as a specific type of glia, but choroid plexus tumors are usually not covered under the umberella term glioma.

By CNS WHO grade

Gliomas are further categorized according to their grade, which is determined by pathologic evaluation of the tumor. Of numerous grading systems in use, the most common is the World Health Organization (WHO) grading system under which tumors are graded from 1 (least advanced disease—best prognosis) to 4 (most advanced disease—worst prognosis). Historically roman numerals were used for grading, but have been replaced by arabic numerals for grading within tumor types. Specific molecular features may influence tumor grading which is now a combination of histology and molecular neuroathology. Grading is based on expected biological behaviour, although proper treatment may heavily change prognosis.

  • Low-grade gliomas [CNS WHO grade 1-2] are well-differentiated (not anaplastic); these tend to exhibit benign tendencies and portend a better prognosis for the patient. However, they have a uniform rate of recurrence and some diffuse gliomas may increase in grade over time and therefore calling these tumours benign is avoided.
  • High-grade [CNS WHO grade 3-4] gliomas are undifferentiated or anaplastic; these are malignant and carry a worse prognosis.

By patient age group

The fifth CNS WHO edition recognizes following categories:

  • Adult-type diffuse gliomas.
  • Pediatric-type diffuse low-grade gliomas.
  • Pediatric-type diffuse high-grade gliomas.
  • Circumscribed astrocytic gliomas.

By location

  • A supratentorial tumour is above the tentorium, in the cerebrum, and mostly found in adults (70%).
  • An infratentorial tumour is below the tentorium, in the cerebellum, and mostly found in children (70%).
  • The pontine is located in the pons of the brainstem. The brainstem has three parts (pons, midbrain, and medulla); the pons controls critical functions such as breathing, making surgery on these extremely dangerous.
  • Anatomic separation is essential in ependymal tumors. They are classfied into three groups:
    • Supratentorial ependymoma.
    • Posterior fossa ependymoma.
    • Spinal ependymoma.


By Molecular profile

Some tumors can only diagnosed after a specific alteration has been confirmed.

Examples are:

Table of common gliomas

Histomorphologic comparison of common gliomas:

Entity Rosenthal
fibres / EGBs		 Nuclear atypia Mitoses Necrosis MVP Infiltrative Image
Pilocytic astrocytoma yes usu. no usu. no usu. no yes no
Rosenthal HE 40x.jpg
Astrocytoma CNS WHO grade 2 no yes no no no yes
Astrocytoma whoII HE.jpg
Astrocytoma CNS WHO grade 3 no yes yes no no yes
Anaplastic astrocytoma - high mag.jpg
Glioblastoma no yes yes yes yes yes
Glioblastoma - high mag.jpg
Oligodendroglioma no usu. no yes no no yes
Oligodendroglioma1 low mag.jpg
Ependymoma CNS WHO grade 2 no usu. no usu. no usu. no no discrete
Ependymoma H&E.jpg
Ependymoma CNS WHO grade 3 no yes yes usu. yes rare discrete
HE anaplastic epedymomas mitoses pleomorphism.jpg

Notes:

  • MVP = microvascular proliferation.
  • EGBs = eosinophilic granular bodies.

See also

Neuropathology tumours

Template:References

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